1. Field
The present embodiments relate to a thin film magnetic head with a metal lamination part.
2. Related Art
As commonly known, a recording element section of a thin film magnetic head includes a lower core layer and an upper core layer that are formed of a magnetic material. A coil layer induces a recording field for the core layers. A magnetic gap layer is interposed between the core layers. The recording element section records magnetic information onto the recording medium using a leakage magnetic field that is generated from the core layers on a surface facing a recording medium through the magnetic gap layer.
Recently, a solenoid-type coil has been wound around the core layers so as to effectively use three-dimensional spaces around the coil layers for the purpose of reducing the size of the recording element section. In the solenoid-type coil, lower coil layers formed below a core layer (for example, a lower core layer) need to be electrically connected to upper coil layers formed on the core layer through contact parts.
For example, the solenoid-type coil layers are formed as described below. First, a lower coil layer made of Cu is formed below a core layer (for example, a lower core layer), and an insulating layer is formed so as to fill the lower coil layer and spaces between pitches of the lower coils, The upper portion of the insulating layer is planarized. The insulating layer is removed from the upper surface of the lower coil layer, and contact parts made of a conductive material are formed by plating in the portions where the insulating layer is removed. Frames are formed on both sides of the contact parts by using a photolithography technique, and each upper coil layer is formed by plating in the spaces between the frames.
After the formation of the upper coil layers, the frames are removed, and the insulating layer is formed so as to fill the lower coils layer and spaces between pitches of the lower coils. The length of wiring lines between each lower coil layer and each upper coil layer is preferably as short as possible to suppress the electric resistance of the interlayer connection, and the contact parts are formed to be adjacent to each other.
The above-mentioned structure has been disclosed in JP-A-2002-150509 (US Publication No. 2004054460A1) and JP-A-2004-296062 (US Publication No. 2004100728A1).
According to a manufacturing method in the related art, the surface of the contact part 30 formed by plating is formed in a convex shape, as shown in FIG. 10A. As shown in FIG. 10B, when the frames are formed in a S photolithography process, light is incident on the convex surface of each contact part and then irregularly reflected from the convex surface during the exposure. The frames 140 are partially cut near the convex surface since the light is irregularly reflected toward the outside. For example, the frames become thin. As a result, an upper coil layer formed in regions surrounded by the frames 140 widens at the portion thereof that comes in contact with the contact part, and the dimension of each frame is deviated from an original design dimension. For example, the pitches of the upper coil layers are varied, and there is a possibility that a short circuit occurs between the coils. In the related art it is not possible to make the thickness of the frame any smaller than a predetermined value and the distance between the adjacent contact parts any smaller, in order to avoid the short circuit.